The present invention relates to a polymer-containing mixture exhibiting elevated resistance to low under the influence or heat.
Because of their organic structure, polymers or plastics are always combustible. Depending on the application of such polymers or plastics this combustibility is dangerous and restricts the use of plastics. There have therefore keen no scarcity of attempts to reduce the combustibility of plastics. For example the plastics may be mixed with fillers in the form of inorganic substances. For example plastics or polymers such as polyvinylchloride, polyolefins, polyamides. polyesters etc., may be mixed homogeneously with fillers such as aluminum hydroxide, magnesium hydroxide, magnesium carbonate, calcium carbonate, silicon oxides etc., in order to reduce the combustibility. In order to reduce the flammability of polymers adequately, the amount of filler material must be increased very greatly, e.g. up to 70 wt. %. This has of course a considerable effect on the properties of the polymers. With an elevated content of filler material the plastic becomes e.g. brittle, losing elasticity in comparison with the starting polymer, which is a disadvantage for many applications. With increasing content of filler material the ease of processing the plastics further decreases and extrusion or calendering processes can be performed only poorly or not at all.
As a rule plastics containing fillers exhibit significantly better performance under conditions of fire i.e. the temperature of ignition is higher and the burning plastic may also be self-extinguishing. With increasing mount of heating, however, the plastics tend to melt and very often polymeric melts that drip while burning are viewed negatively. This type of behavior is very pronounced e.g. in the case of polyolefins such as polyethylene and polypropylene. On the other hand plastics from the polyolefin group are among the most preferred plastics as they are easy to process, contain no heavy metal additives, are easy to recycle, and in case of fire release no toxic substances.